Valves



y 16, 1957 F. M. VAN DEVENTER 2,799,468

VALVES Filed Jan. 19, 1951 ""&\"

all/I INVENTOR. fianIZ'M lizaflewzzcfel? wromvy United t VALVESApplication January 19, 1951, Serial No. 206,821

6 Claims. (Cl. 251-124) This invention relates to valves and, moreparticularly, to plug valve assemblies for pressure recovery purposesand is a continuation-in-part of my copending application Serial No.25,002, filed May 4, 1948, now Patent No. 2,717,758 granted September13, 1955.

In the conventional design of plug valves, the relatively abruptenlargement of flow area from the plug to the downstream port of thevalve necessarily involves a pressure drop in the fluid being conveyedtherethrough. Such pressure drop becomes cumulative in long pipe lineswhere a multiplicity of plug valves is installed at intervals in theline.- This reduces the amount of fluid which can be transported througha given size pipe and necessitates an increase in the power required toforce a given quantity of fluid through the line.

The problem has been accentuated over a period of years due to thedevelopment of larger and larger pipe lines, particularly forcross-country use. The increased cost of valves comparable in size tosuch lines has led to the use of smaller valves in an endeavor to reducethe overall capital investment. Consequently, a considerable increase inpressure loss as compared to that through full size valves has beenencountered. This has restricted the usefulness of plug valves despitedefinite advantages which this type of valve possesses; one particularadvantage being that plug valves readily lend themselves to theapplication of lubricating principles which are now embodied in thewell-known lubricated plug valve.

In the said copending application, a rotatable plu member engages theseating surface of the valve casing and is provided with a port ofsubstantailly rectangular cross-section. The casing has an inlet on oneside of the plug member having a tapered opening of approximately 40included angle converging for registry with the port. An outlet ispositioned in the casing on the opposite side of the plug member and hasa tapered opening of substantially rectangular cross-section divergingfrom registry with the port. The outlet has an included angle in itsmajor dimension of approximately The center-toface dimensons of theinlet and outlet sides of the valve casing are approximately the same.

The pressure recovery tube of the copending application is connected atone end to the larger end of the outlet and is adapted at its oppositeend for connection to the opposite end of the pipe line. Necessarily,the recovery tube has a generally rectangular cross-section at the oneend and a circular cross-section at the opposite end. The contour of thetube thus merges from the generally rectangular small end to thecircular large end and requires special fabrication from metal plate.Moreover, reinforcing ribs are required to supplement the normalstrength of the metal plate in this prior construction.

- The present disclosure involves a valve casing'wherein the inlet isconstructed as in the prior disclosure, but the outlet is extended to agreater length so that the cens atent O ter-to-face dimensions differ.The outlet end is of sufficient length so that the juncture with therecovery tube is of circular form. The tube may thus be fabricated theshape of a true frustum of a cone. Thus, the manufacturing cost isgreatly lessened and the reinforcing ribs may be dispensed with.

Other objects and adva'ntages'include a substantial reduction inpressure loss through the valve; the ability to use valves of smallerrated size than the pipe line; the retention of the conventional form ofport opening; the effective utilization of the increase in velocitywhich accompanies pressure .drop to produce a pressure recovery; theincrease inthe conversion of the velocity into pres-v sure to asubstantially high efficiency; and the combination of slight structuralchanges in the plug valve with corresponding changes in the adjacentpipe line section at its outer or larger .end as indicated in Fig. 1.

to produce a high overfall efliciency.

Other objects and advantages will become apparent from the followingdescription taken in connection with the accompanying drawings wherein:

Fig. 1 is a longitudinal sectional plan view of a plug valve and pipeline assembly embodying the invention.

Fig. 2 is a longitudinal sectional elevation corresponding to Fig. 1;and

Figs. 3 through 6 are cross-sectional views on lines III-Ill throughVI-VI respectively of Fig. 2.

Referring more particularly to the drawing, the plug valve element ofthis invention is shown as comprising a lubricated plug valve 10 ofconventional form but modi-- fied slightly as will appear hereinafter.The plug valve 10 comprises a casing 12 having a seating surface 14therein which may be of conical form and provided with lubricatinggrooves (not shown) as is customary. A rotatable plug member 18 ispositioned in the casing 12 and may be of conical form for cooperationwith the seating surface 14.

The plug member 18 is provided with a stem 20, shown partly broken awayin Fig. 2, by means of which it can be rotated through an angle ofapproximately 90 defining the open and closed positions of the valve.The remaining portions of conventional lubricated plug valves arewell-known and further description is deemed unnecessary.

The plug member 18 is provided with a port 24 extending therethrough andwhich is generally rectangular or, more specifically, of trapezoidalform as indicated in Fig. 3. When the plug member 18 is in the openposition shown in Fig. 1, fluid is admitted thereto from an inlet 26 andis conveyed therefrom by an outlet 28 which openings are positionedrespectively on the casing 12 on opposite sides of the plug member 18.In this embodiment of the invention, the inlet 26 is of conventionalform and requires no changes to adapt it for accomplishing theprinciples of the invention. However, the outlet 28 is modified from theconventional form and thereby the objects and advantages of thisinvention are achieved.

Accordingly, the inlet 26 is of hollow, tapered construction having atapered opening 36 which converges from the outer end of the inlet 26for registry with the adjacent end of the port 24 in the plug member 18.The included angle X of the tapered opening 30 is usually degrees ormore and, as will appear hereinafter is therefore more obtuse than thatof the outlet 28. The opening 30 preferably merges from a trapezoidalform at its inner or smaller end conforming to the shape of the. port 24into a substantially circular opening 34 The outeren'd '34 of the inlet26 terminates in a welding portion. which is shown as welded to a pipesection 3 8.- Consequently,',thediameter or" the circular outer endportion .34 .is substantially equal to that of .the pipe section 38. Aspreviously mentioned, the inlet 26 is of generally conventional form andconsequently an abrupt change from one area to another occurs in thefiuid passing from the pipe section 38 through .the inlet 26 to the port24. It will be'apparent that when a similar abrupt change occurs in areverse direction,'such *as 'when'the fluid emerges from the port24'into a conventional outlet, there is aconsiderable restriction offlow areain the central portion of the valve body which bears someresemblance to a Venturi tube. However, only a slight loss occurs in theconverging or inlet channel and some of the fluid pressure is convertedinto velocity of the fluid.

This invention is more particularly concerned with recovery of fluidpressure. It is well-known that the clfectiveness of reconversion ofvelocity into pressure in the downstream channel of a Venturi tubedepends upon the difference in flow area at the throat as compared tothe area at the mouth; but, more importantly, it depends upon the anglebetween the sides of the flow channel. When this angle is 80 or-more, asin the case of conventional valves, the loss due to turbulence and shockis as great as though the change in section were an abrupt enlargement,i. e., an immediate change from one area to a larger area. In thisinvention, certain changes have been made in the outlet port of theotherwise conventional valve but in combination with supplementarystructure also to be described. The combination provides a continuousflow channel beginning at the valve plug member 18 of such proportionsas to accomplish a highly efiicient conversion of the velocity intopressure.

To this end, the outlet 28 of hollow, tapered construction is providedwith a tapered opening 40 which diverges from registry with the port 24.The inner end of the outlet opening 40 conforms in cross-section to thetrapezoidal shape of the port 24. The outer end 42 of the outlet opening40 is substantially circular as in the case of the outer end 34 of theinlet opening 30, but the diameter of the outer end 42 is approximatelyone half the diameter of the outer end 34. Specifically, the includedangle Y of the opening 40 should be approximately 10 as shown in thehorizontal section, Fig. 1. It will be observed that in the verticalsection, Fig. 2 the sides of the outlet opening 40 converge toward theouter end 42 thereof. The convergence may or may not be requireddepending upon the selected diameter of the dis charge opening and theselected center-to-face dimension of the outlet opening 40.

As in the case of the inlet 26, the outlet 28 terminates in a weldingend connection at the outer end 42 which is shown as welded to one endof a tubular pipe section 44. The tube 44 is of frustro-conical formhaving an included angle of approximately 10 to form an extension of theoutlet opening 40. The outer end 46 of the tube 44 preferably has adiameter approximately equal to the diameter of the outer end 34 of theinlet opening 30. Consequently, a section of the pipe 38 may be securedas by welding to the end face 46. As shown in the sectional views Figs.4, 5 and 6, the tubular pipe section 44 forms a true frusturn of a conesince the various diameters along its length are substantially circular.

As will be apparent, the pipe line 38 has a crosssectional areasubstantially in excess of that of the port 24. Since one of theimportant advantages of the invention is that it permits the economicaluse of valves of smaller size than the pipe line, such reduction incrosssectional area may be intentional. For example, with a thirty-inchdiameter pipe line 38 there could be used a valve with a standardso-called twenty-four inch plug usual trapezoidal shape at the plug port24 to a circular cross-section having an internal diameter ofapproximately sixteen inches, Inasmuch as it has been stated that the715,

.included angle approximates 10, the center-to-face dimension of theoutlet 28 in the example is forty-six inches, which dimension results inan included angle of 11 plus. In any event, the outlet 28 will have acenterto-face dimension substantially greater than that of the inlet 26.

It will be understood that valves with one or more flanged ends forbolting to the pipe line could equally well be used in place of thewelding end valve shown and described herein. These and othermodifications and changes in the arrangement and combination of partsand in the details of construction can be made without departure fromthe scope of the invention as defined in the appended claims.

I claim:

1. A plug valve assembly adapted for insertion between the ends of apair of oppositely disposed tubular pipe sections comprising a valvecasing having opposite end portions, one of said casing portionsdefining an inlet passage converging in one direction to a tapered valveseat from substantially the diameter of one of the pipe sections Withwhich it is adapted to be associated, the other of said casing portionsincluding an outlet passage extending in an opposite direction from saidvalve seat, a tapered plug valve member cooperable with said seat andhaving a port of substantially rectangular cross section, said passageshaving at least the portions thereof adjacent the valve seat formed ofsubstantially rectangular cross section with which said plug port isadapted to register to form a supplemental connecting conduit in theopen position of said valve member, said outlet passage diverging alongat least the minor dimension thereof to the terminus of said othercasing portion and terminating in an outlet port of generally circularcross section having a cross sectional area substantially less than thecross sectional area of the inlet opening of said one casing portion,and a frustro-conical pipe section positioned at said outlet port ofsaid outlet passage and engaging at its smaller end with said othercasing portion, said pipe section having an included angle ofapproximately ten degrees and being adapted to be connected at thelarger end thereof to the other of the tubular pipe sections.

2. A plug valve assembly as claimed in claim 1 wherein the includedangle in the plane of the minor axes of serial cross sections of saidoutlet passage is approximately ten degrees.

3. A plug valve assembly as claimed in claim 2 wherein said outletpassage converges along the major dimension thereof.

4. A plug valve comprising a valve casing having opposite end portions,one of said casing portions defining an inlet passage converging from aninlet port to a tapered valve seat, the other of said casing portionsincluding an outlet passage extending from said valve seat, a taperedplug valve member cooperable with said seat and having a port ofsubstantially rectangular cross section, said passages'having at leastthe portions thereof adjacent the valve seat formed of substantiallyrectangular cross section with which said plug port is adapted toregister to form a supplemental connecting conduit in the open positionof said valve member, said outlet passage diverging along at least theminor dimension thereof to the terminus of said other casing portion andterminating in an outlet port of generally circular cross section havinga cross sectional area substantially less than the cross sectional areaof said inlet port in said one casing portion.

5. A plug valve as claimed in claim 4 wherein the included angle in theplane of the minor axes of serial cross sections of said outlet passageis approximately ten degrees.

6. A plug valve as claimed in claim 5 wherein said outlet passageconverges along the major dimension thereof.

(References on following page) References Cited in the file of thispatent UNITED STATES PATENTS OTHER REFERENCES A. S. M. E. ResearchPublication, Fluid Meters (137- 714).

D F t- I 29, 1907 g j fi jj 23, 1915 5 Text on Hydrauhcs (4th ed.).(Copy 1n Llbrary of D F a t' De .11,1917 Congrm) s g jj 13, 1925 Text onHydraulies, by Hughes and Safford, pp. 225- Hamer June 10 in DivislonFOREIGN PATENTS Great Britain Dec. 2, 1909 10 France Mar. 31, 1911 GreatBritain Dec. 18, 1930

